Tilted structures to reduce reflection in laser-assisted TAMR

1. A TAMR (thermally assisted magnetic recording) head slider, comprising: a slider substrate having a horizontal planar back end surface and a horizontal planar ABS (air bearing surface); a magnetic write element, emerging at said ABS which produces a magnetic field for writing on a magnetic recording medium rotating beneath said horizontal planar ABS end; a waveguide extending through said slider from said slider back end surface to said slider ABS end, wherein said waveguide has a dielectric core and is surrounded by a dielectric cladding, wherein said waveguide propagates optical frequency electromagnetic radiation along a centerline direction towards said slider ABS end, wherein said waveguide has a planar back end surface that is coplanar with said slider back end surface, at which back end surface said optical frequency electromagnetic radiation couples with said waveguide and; wherein said waveguide has a planar ABS end, and wherein said planar ABS end lies within said slider ABS or is tilted relative to said slider ABS end; and wherein a laser diode source of optical frequency electromagnetic radiation is affixed to said planar back end surface of said slider; wherein an exit facet of said laser diode source is electromagnetically coupled to said waveguide at said planar backside end of said waveguide; wherein said laser diode includes a linear resonant cavity having a central axis of symmetry, wherein said central axis of symmetry of said linear resonant cavity is aligned at an angle to a normal to said backside end of said waveguide; and wherein a plasmon generator is formed between said write element and said waveguide; wherein said plasmon generator has a central axis of symmetry and is positioned adjacent to said waveguide at said ABS end of said waveguide and separated from said waveguide; wherein said electromagnetic radiation is coupled to a plasmon mode in said plasmon generator; wherein said centerline direction of said waveguide at said backend surface of said waveguide is tilted relative to said central axis of symmetry of said laser diode cavity or is not tilted relative thereto; wherein said centerline direction of said waveguide is tilted relative to either said planar backside surface or said planar ABS or both said surfaces, whereby; reflections of said electromagnetic radiation, originating at interfacial surfaces and at regions of radiative coupling and proceeding in a direction back towards said laser diode are suppressed by failing to satisfy critical angle criteria set by dielectric constants of said core dielectric material and dielectric cladding material and wherein cavity modes of said laser are thereby stable.

2. The TAMR head slider of claim 1 wherein said resonant cavity from which said laser radiation is emitted has an axis of symmetry that is tilted in a x-z plane at an angle to a normal to said backside end of said waveguide.

3. The TAMR head of claim 1 wherein said axis of symmetry of said resonant cavity of said laser diode is tilted in a y-z plane but is not tilted in an x-z plane and wherein said laser diode is affixed to a submount having a planar bottom surface and a tilted front face to support said laser diode and wherein said submount planar bottom surface is affixed to said backside surface of said slider.

4. The TAMR head of claim 1 wherein said laser diode comprises a cavity that is a Fabry-Perot resonant cavity formed by parallel crystallographic planes cleaved from a laser diode wafer.

5. The TAMR head of claim 4 wherein said laser diode is tilted by scribing and tilting cleavage planes forming lateral sides of said cavity.

6. The TAMR head of claim 3 wherein said submount is a silicon submount whose mounting surfaces are tilted relative to a vertical direction machining or tilt-lapping.

7. A method of forming a TAMR (thermally assisted magnetic recording) head slider, comprising: providing a slider substrate having a horizontal planar backside end surface and a horizontal planar ABS (air bearing surface) end and including a read/write element embedded in said ABS; forming a waveguide in said slider substrate, said waveguide extending through said slider from said slider backside end surface to said slider ABS end, wherein said waveguide has a dielectric core and is surrounded by a dielectric cladding, wherein said waveguide propagates optical electromagnetic radiation along a centerline direction towards said slider ABS end, wherein said waveguide has a planar backside end at which backside end electromagnetic radiation enters said waveguide and wherein said waveguide has a planar ABS end and wherein said planar ABS end lies within said slider ABS or is tilted relative to said slider ABS; forming a laser diode source of said electromagnetic radiation and affixing said laser diode source to said planar back end surface of said slider, wherein said laser diode includes a cavity resonator having a central axis of symmetry and wherein an exit facet of said laser diode source is tilted relative to said central axis of symmetry of said resonant cavity and abuts said planar backside end of said waveguide and is thereby optically coupled to said waveguide; forming a plasmon generator between said write element and said waveguide wherein said plasmon generator has a central axis of symmetry and wherein said plasmon generator is adjacent to said waveguide at said ABS end of said waveguide, whereat said electromagnetic radiation in said waveguide is coupled to a plasmon mode within said plasmon generator; wherein said centerline direction of said waveguide is tilted relative to either said planar backside surface or said planar ABS or both said surfaces, whereby; reflections of said electromagnetic radiation in a direction back towards said laser diode are suppressed and wherein cavity modes of said laser are thereby stable.